1. Technical Field
The present invention relates generally to nasal oxygen cannula technology, and in particular, to an apparatus and method for stabilizing and anchoring nasal oxygen cannulas in a secure and comfortable manner.
2. Description of the Related Art
Nasal oxygen cannulas are utilized to deliver oxygen directly to nasal airways in order to infuse oxygen into the inspirational airflow of patients in need of such therapy. Typically, these systems include a relatively large bore plastic supply tube as a conduit for providing gas flow from a pressurized oxygen source to proximal ends of a pair of plastic oxygen delivery tubes having relatively smaller bores. In a typical nasal cannula configuration, the distal ends of the delivery tubes enter into opposite ends of a short, expanded piece of plastic tubing, referred to herein as an oxygen delivery barrel. In the foregoing manner, the oxygen delivery barrel joins the two oxygen delivery tubes in a loop configuration. The barrel is typically cylindrical in shape, formed of a short length of enlarged plastic tubing provided with smaller diameter, stub-like extensions referred to herein as cannula delivery ports. The ports are open at their distal ends and are positioned in circumferential alignment upon the barrel and transverse to the longitudinal axis of the barrel. The cannula delivery ports are positioned so that the distance therebetween approximates an average distance between the nares in which they will be positioned. The terms “cannula,” “nasal cannula,” and “nasal oxygen cannula” are utilized throughout this specification and within the claims interchangeably, and refer, collectively and individually to an apparatus or device comprised of various tubing and associated retention/anchoring structure for delivery oxygen or other respiratory gases or mixtures of respiratory gases to a patient through the patient's external nasal passages.
An example prior art nasal oxygen cannula design is depicted in FIG. 1. Starting at the distal end, as shown in FIG. 1, the nasal cannula includes a tube coupler 62 designed to mate to an oxygen supply tube fitting (not depicted) on its proximal end. The distal end of tube coupler 62 joins with a single lumen supply tube 64 that branches into a pair of oxygen delivery tubes 68 which in turn terminate at an oxygen supply barrel 63. With the bores of the oxygen supply tube, oxygen delivery tubes, oxygen supply barrel and delivery ports in mutual fluid communication, oxygen is supplied from a pressurized oxygen source to the proximal end of the single lumen supply tube 64 from which it flows into delivery tubes 68 and into the patients nasal passages through a pair of oxygen ports 65 protruding from delivery barrel 63. The source oxygen supply is typically pressurized with the patient's inspirational airflow assisting the oxygen intake.
To ensure adequate and uninterrupted oxygen delivery, nasal cannulas must be securely positioned such that the delivery ports on the oxygen supply barrel are maintained in secure alignment with a patient's nostrils. Conventional catheter/cannulas have largely depended upon the use of the pair of oxygen delivery tubes, such as those depicted in FIG. 1, to stabilize the barrel's position under the nose and thereby maintain the cannula delivery ports within the patient's nostrils. By looping each of two delivery tubes over the top of each ear, a portion of the tube becomes trapped in the sulcus area between the ear and the skin of the head. The traction provided by trapping the tubes within the sulcus, prevents free movement of the delivery tubes and thus provides stabilization of the oxygen delivery barrel under a patient's nose.
The delivery tube ear loop design of the apparatus shown in FIG. 1 achieves limited cannula stabilization that resists displacement of the delivery ports upon movement of the patient's head. However, there are also many disadvantages and limitations related to utilizing this conventional apparatus and method. For example, patients tend to move their heads during sleep, resulting in an associated movement of the pair of oxygen delivery tubes looped behind the ears. Movement of these tubes often causes irritation, abrasion and pain arising from friction at the skin folds comprising the sulcus between the ear and lateral head area. Responsive to such irritation and pain, patients often “shake off” the catheter/cannula resulting in considerable sleep interruption and, more importantly, interruption of the patient's necessary oxygen supply.
The above-described cannula positioning/retention problems are, to some extent, addressed by U.S. Pat. No. 6,093,169 (the '169 patent). To improve retention of the cannula delivery ports within the nostrils, the '169 patent discloses. a detachable retainer that is positioned along the ridge pole of the nose. The ridge pole retainer is generally configured as an L-shaped strut having a long “leg” and a short “leg.” The long leg of the strut is configured and adapted to conform to and lie upon the ridge pole of the nose from the root of the nose to an area proximate to the tip of the nose. The strut is comprised of a flexible material such as a plastic or fabric covered/padded metal framework that may be secured to the ridge pole of the nose with a suitable adhesive means. The short leg of the strut lies in an angular relationship with the long leg such that it may be positioned under the nose, generally in line with the nasal septum.
The short leg also includes, in certain preferred embodiments, a curved portion that is especially adapted and configured to pass around and securely retain an oxygen delivery barrel. The barrel is thus held and secured in a position and orientation that assures that cannula delivery ports protruding transversely therefrom remain secured within a patient's nostrils.
As described above, the device disclosed by the '169 patent is advantageously comprised of a springy plastic or springy metal backbone demonstrating high elastic memory within operational limits. The contour and elasticity of the device provide a traction force to the nose when the device is secured along the ridge pole of a patient's nose. The traction force of the device, so applied and secured, tends to pull the tip of the wearer's nose both upward and inward. More specifically, as the long arm of the retainer is urged upward towards the root of the nose, the short leg flange portion pulls the tip of the nose upward and inward towards the forehead. The pulling upward and inward of the tip of the nose tends to shorten and increase the diameter of the external nasal airway. As a result, the external nasal bore, widened and shortened, provides decreased airway resistance, allowing greater inspiration and more efficient oxygen delivery to the patient, while simultaneously providing improved stabilization and retention of the oxygen delivery barrel under the patient's nose.
Although the device described by the '169 patent provides increased cannula stabilization, it is still utilized with the above-described ear loops in order to further stabilize the device. Thus, although greater stability is provided by the cannula support device described therein, a patient remains susceptible to irritation, abrasion and resultant “throw off” associated with such loops.
What is needed is a nasal cannula device and method of utilizing same, which provides the increased stabilization and increased airway efficiency demonstrated by the '169 patent, while, at the same time, eliminating the use of ear loops and the irritations and abrasions associated with the use thereof. The present invention addresses such a need.